“An earthquake is such fun when it is over.” – George Orwell
A long time ago, our ancestors believed earthquakes to be the act of the Gods. Aristotle, a Greek philosopher, was the first to realise that earthquakes were more than an act of the Gods. To this day, STEMists continue to tame the devastating effects earthquakes have on human lives, buildings, roads, and power supplies.
How do people build structures that resist earthquake damage? Well, in the past it wasn’t really possible. The building materials available were limited to stone, brick, wood, thatch – none of them good for surviving earthquakes or high winds. Modern skyscrapers are made possible by modern building materials, especially steel.
What is steel?
Steel is iron mixed with other substances and/or given special treatments. Carbon steel is iron mixed with carbon. Depending on the amounts of each element, carbon steel can be brittle and hard like cast iron (e.g. a skillet) or soft and workable like wrought iron (think of a groovy iron gate.)
Alloy steel is iron mixed with other metals such as chromium, nickel, or vanadium. The metals in the mix are chosen to make the iron stronger or lighter. Tool steel is specially treated to be strong through a process called tempering. The steel is quickly heated to a high temperature, quickly cooled (quenched) and heated again to a lower temperature. Finally, stainless steel is mixed with high amounts of chromium and nickel to make it smooth, easy to clean and polish. Stainless steel is used for eating utensils and surgical instruments.
How do STEMists make buildings earthquake resistant?
The more lightweight and flexible a building is, the better it can withstand the lateral (sideways) forces of an earthquake. Skyscrapers are built around a steel frame that supports the weight of the walls and floors. Regular buildings use the walls to support the weight of the house or other structure, but in a skyscraper the weight of all those upper walls would be too much for the lower walls to support. Steel makes tall buildings possible.
The foundation of a skyscraper is extremely important. Think of a pyramid with its wide base. Would it stand as well if turned upside down? Of course not! Base-isolation, an engineering design, is used to prevent damage to buildings from the seismic impact from earthquakes. This technique where the bottom section of a building absorb the seismic waves of energy to prevent damage, was used as far back as the Mausoleum of Cyrus.
Skyscrapers are placed on a foundation designed to absorb vibrations from earthquakes. Architects design flexible springs and cushioned cylinders to act as shock absorbers. Think of the shock absorbers on a car. Without proper shocks, the car would bounce dangerously as it moved over potholes or railroad crossings. The shocks keep all the tires on the ground despite bumps, just as a building’s foundation keeps the building from tipping or moving off the foundation.
A shake table is a device used to determine how well a building will react to earthquakes. To see how well structures will react to earthquake shocks, building models are placed on massive outdoor shake tables and subjected to an array of ground motion energy.
Burj Khalifa building in Dubai
The Burj Khalifa, the world’s largest skyscraper, is so tall the tip of the top sphere is visible from 95 kilometers away on a clear day. It has an enormous “mass dampener” or harmonic absorber. This is a device mounted inside skyscrapers to absorb vibrations that might otherwise damage the building. The aluminum used in the building weighs as much as five A380 aircraft and the concrete weighs as much as 100,000 elephants. The Burj Khalifa’s aesthetic and environmental design mimics the look of a hymenocallis flower with its shaped central spire while collecting 15 million gallons of water every year.
Taipei 101 building in Taiwan
In Taiwan, the Taipei 101 building (over 449 meters high) includes a central column that acts as a pendulum to balance the sideways movement of seismic waves from earthquakes and typhoons. Architects got this idea from ancient pagodas (temples) which have stood for centuries in earthquake-prone areas. The Japanese used the same pagoda idea when they built the Yokohama Landmark Tower (296 meters tall.)
Petronas Towers in Kuala Lumpur, the capital of Malaysia
The Petronas Towers in Kuala Lumpur, Malaysia, stand 452 meters high. They were the tallest buildings in the world until 2004 and remain the tallest twin towers in the world. They include the world’s tallest 2-story bridge connecting the 41st and 42nd floors. The bridge is designed to slide in and out of the buildings as the wind causes the buildings to sway–safer than a rigid design would be.
U.S. Bank Tower in Los Angeles
In the United States, earthquakes are most closely associated with the state of California, although there are fault lines in other areas of the country as well. The U.S. Bank Tower in Los Angeles is 310 meters high. It is also known as the Library Tower because it includes a restored Los Angeles library.
TransAmerica Pyramid in San Francisco
Another famous skyscraper in California is the TransAmerica Pyramid in San Francisco. This elongated pyramid was built to allow sunlight to reach the surrounding areas in spite of the building’s height of 260 meters. That was pretty groovy for them to do for their not so tall neighbors. Because of the shape of the building, the majority of the windows can pivot 360 degrees so they can be washed from the inside. The spire is actually hollow and lined with a 100-foot steel stairway at a 60 degree angle, followed by two steel ladders. There used to be a public observation deck on the 27th floor, but it was closed after 9/11. That means you can only check out the view by looking at the live feeds at the Visitor Center.
There is a commemorative plaque in honor of Bummer and Lazarus, the famous dogs of the 1850s, at the base of the building.
Buildings of the Future
The Wilshire Grand Tower
The Wilshire Grand Tower will be 335 meters tall when completed. It will then be the tallest building in Los Angeles and the tallest building west of the Mississippi River.
Salesforce Tower (once called the Transbay Tower)
Also being built in San Francisco is the Salesforce Tower (once called the Transbay Tower.) This building will be 326 meters tall and second tallest building west of the Mississippi. It was begun in 2013 and is expected to be open in 2018.
Architects and engineers are always looking for new ideas to build groovier buildings, especially in earthquake-prone areas. Old ideas like the pagoda and new ideas like modern alloy steel and harmonic absorbers can combine to make buildings that look groovy and stand tall through the forces of nature.
Learn More about earthquakes and earthquake proof structures with “Shake It Up” Groovy Lab in a Box!
“Shake It Up” Engineering Design Challenge: You are a groovy earthquake engineer who has been contracted by the city of Los Angeles. Using only the materials from your Groovy Lab in a Box, can you design and build the tallest skyscraper that can withstand the next BIG quake?
During their engineering design process, STEMists will investigate what causes earthquakes while constructing a groovy seismograph and shake table. Explore S and P waves, fault planes, famous earthquake proof structures around the world and much, much more! From their groovy lab notebook, STEMists do investigation activities which work in tandem with the special “Beyond…in a Box” online learning portal. This is a unique feature of Groovy Lab in a Box because it gives STEMists a deeper understanding of that month’s topic. “Beyond…in a Box” has videos, reading library and more interactive activities to supplement what they are learning from the box projects, which also helps the STEMist even more when completing the design challenge.
Join Now! and challenge your STEMists to a monthly Groovy Lab in a Box, full of everything a child needs to learn about and do hands-on science, technology, engineering, and mathematics (STEM) investigations and engineering design challenges. Our monthly box activates thinking, questioning, inquiring and original creation as we guide children through scientific inquiry and the engineering design process.